| As cave-dwelling fish,Triplophysa rosa have the degeneration of eyes and pigmentation in bodies owing to living in the dark environment,like other reported cave fish,such as Astyanax mexicanus.However,when these cave fishes were grasped and raised in the natural lighting surrounds depart from habitat for 7~14 days,surprisingly,a part of the population with proximity to 50% got the dark strip patterns pigmentation over the whole body except the ventral side and the others did not and kept albinism.It is suggested that T.rosa is still in possession of the ability of producing melanin by itself.It is extremely different from other reported cave fishes and probably owing to the new origin of T.rosa.And the genetic basis of T.rosa albinism is significant and subservience for us to explore the process of being albinism during regressive evolution in cave-dwelling organisms.This research is aimed at as followes:(1)Using RNA-seq technology to explore the basic of the albinism in T.rosa.(2)Investigating the role of key genes of pigment in adaptive evolution.The main studies are two folds:(1)Investigate the genetic basis of the albinism in T.rosa via RNA-seq.(2)Analyse the predicted tyrp1 gene based on the RNA-seq data of T.rosa.The main results are as follows:(1)The de novo transcriptome for 12 tissues,contain the brains and skins from 6 T.rosa individuals was performed using Hiseq2500,and 79.12 GB Clean Reads(Q30>92%)were produced.The filtrated reads were assembled by Trinity,291,122 Unigenes(N50 is 2,308)were gained,and the mapped ratio is greater than 81%.it shows that the assembling is integrity.And 96,689 available annotated Unigenes(COG,GO,KEGG,KOG,Pfam,Swissprot,and nr databases were used for annotating)were aquaired.(2)We identified 244 differently expressed genes(DEGs)between the albino T.rosa and melanin pigmented T.rosa,177 up-regulated and 67 down-regulated in the black.155 DEGs were annotated to Gene Ontology(GO),130 were annotated to Molecular function,102 were annotated to Cellular Component,113 were annotated to Biological Process,contain 355 GO terms,the most enriched are ATP binding(n=22),integral component of membrane(n=22),regulation of transcription DNA-templated(n=10)separately.128 DEGs were annotated to KEGG pathway,the top 10 enriched are Calcium signaling pathway,RNA transport,MAPK signaling pathway,Carbon metabolism,Tight junction,RNA degradation,Protein processing in endoplasmic reticulum,Cardiac muscle contraction,Biosynthesis of amino acids,Arginine and proline metabolism.(3)The expression of dusp6、hspa5、map2k4 and mef2 c genes from MAPK is significantly different(p<0.01)between the albinism and the black.And dusp6 and map2k4 are up-regulated in the black,and the others are down-regulated.It is implied that MAPK signaling pathway and these involved genes are possibly related to the albinism of T.rosa.(4)Using the RNA-seq data and the unpublished genomic-seq data to analyse the alternative splicing and the exons of predicted tyrp1 gene,which is related to melanin synthesis,in T.rosa.Then we predicted that this gene has 7 exons,contains two splice variants(TX-1 and TX-2,consists of 1,596 bp and 1,521 bp respectively)in skin,and the alternative splicing occurs at the region from 1,237 bp to 1,335 bp.Surprisingly,a premature stop codon located in the position of C417 N,at exon 6 of predicted TX-1,and it expresses in rosa skin and there is no significant difference between the albino and the black(p>0.1).It implied that this premature stop codon dose not effect the transcription of tyrp1 gene. |
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